* nor take the bus's rwsem. Please verify those are accounted
* for before calling this. (It is ok to call with no other effort
* from a driver's probe() method.)
+ *
+ * This function must be called with @dev->sem held.
*/
void device_bind_driver(struct device * dev)
{
pr_debug("bound device '%s' to driver '%s'\n",
dev->bus_id, dev->driver->name);
- klist_add_tail(&dev->driver->klist_devices, &dev->knode_driver);
+ klist_add_tail(&dev->knode_driver, &dev->driver->klist_devices);
sysfs_create_link(&dev->driver->kobj, &dev->kobj,
kobject_name(&dev->kobj));
sysfs_create_link(&dev->kobj, &dev->driver->kobj, "driver");
* because we don't know the format of the ID structures, nor what
* is to be considered a match and what is not.
*
- * If we find a match, we call @drv->probe(@dev) if it exists, and
- * call device_bind_driver() above.
+ *
+ * This function returns 1 if a match is found, an error if one
+ * occurs (that is not -ENODEV or -ENXIO), and 0 otherwise.
+ *
+ * This function must be called with @dev->sem held.
*/
int driver_probe_device(struct device_driver * drv, struct device * dev)
{
- int error = 0;
+ int ret = 0;
if (drv->bus->match && !drv->bus->match(dev, drv))
- return -ENODEV;
+ goto Done;
- down(&dev->sem);
+ pr_debug("%s: Matched Device %s with Driver %s\n",
+ drv->bus->name, dev->bus_id, drv->name);
dev->driver = drv;
if (drv->probe) {
- error = drv->probe(dev);
- if (error) {
+ ret = drv->probe(dev);
+ if (ret) {
dev->driver = NULL;
- up(&dev->sem);
- return error;
+ goto ProbeFailed;
}
}
- up(&dev->sem);
device_bind_driver(dev);
- return 0;
-}
-
-static int __device_attach(struct device_driver * drv, void * data)
-{
- struct device * dev = data;
- int error;
-
- error = driver_probe_device(drv, dev);
+ ret = 1;
+ pr_debug("%s: Bound Device %s to Driver %s\n",
+ drv->bus->name, dev->bus_id, drv->name);
+ goto Done;
- if (error == -ENODEV && error == -ENXIO) {
+ ProbeFailed:
+ if (ret == -ENODEV || ret == -ENXIO) {
/* Driver matched, but didn't support device
* or device not found.
* Not an error; keep going.
*/
- error = 0;
+ ret = 0;
} else {
/* driver matched but the probe failed */
printk(KERN_WARNING
"%s: probe of %s failed with error %d\n",
- drv->name, dev->bus_id, error);
+ drv->name, dev->bus_id, ret);
}
- return 0;
+ Done:
+ return ret;
+}
+
+static int __device_attach(struct device_driver * drv, void * data)
+{
+ struct device * dev = data;
+ return driver_probe_device(drv, dev);
}
/**
* Walk the list of drivers that the bus has and call
* driver_probe_device() for each pair. If a compatible
* pair is found, break out and return.
+ *
+ * Returns 1 if the device was bound to a driver;
+ * 0 if no matching device was found; error code otherwise.
*/
int device_attach(struct device * dev)
{
+ int ret = 0;
+
+ down(&dev->sem);
if (dev->driver) {
device_bind_driver(dev);
- return 1;
- }
-
- return bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
+ ret = 1;
+ } else
+ ret = bus_for_each_drv(dev->bus, NULL, dev, __device_attach);
+ up(&dev->sem);
+ return ret;
}
static int __driver_attach(struct device * dev, void * data)
{
struct device_driver * drv = data;
- int error = 0;
-
- if (!dev->driver) {
- error = driver_probe_device(drv, dev);
- if (error) {
- if (error != -ENODEV) {
- /* driver matched but the probe failed */
- printk(KERN_WARNING
- "%s: probe of %s failed with error %d\n",
- drv->name, dev->bus_id, error);
- } else
- error = 0;
- }
- }
+
+ /*
+ * Lock device and try to bind to it. We drop the error
+ * here and always return 0, because we need to keep trying
+ * to bind to devices and some drivers will return an error
+ * simply if it didn't support the device.
+ *
+ * driver_probe_device() will spit a warning if there
+ * is an error.
+ */
+
+ down(&dev->sem);
+ if (!dev->driver)
+ driver_probe_device(drv, dev);
+ up(&dev->sem);
+
+
return 0;
}
* match the driver with each one. If driver_probe_device()
* returns 0 and the @dev->driver is set, we've found a
* compatible pair.
- *
- * Note that we ignore the -ENODEV error from driver_probe_device(),
- * since it's perfectly valid for a driver not to bind to any devices.
*/
void driver_attach(struct device_driver * drv)
{
* @dev: device.
*
* Manually detach device from driver.
- * Note that this is called without incrementing the bus
- * reference count nor taking the bus's rwsem. Be sure that
- * those are accounted for before calling this function.
+ *
+ * __device_release_driver() must be called with @dev->sem held.
*/
-void device_release_driver(struct device * dev)
-{
- struct device_driver * drv = dev->driver;
- if (!drv)
- return;
-
- sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
- sysfs_remove_link(&dev->kobj, "driver");
- klist_remove(&dev->knode_driver);
+static void __device_release_driver(struct device * dev)
+{
+ struct device_driver * drv;
+
+ drv = dev->driver;
+ if (drv) {
+ get_driver(drv);
+ sysfs_remove_link(&drv->kobj, kobject_name(&dev->kobj));
+ sysfs_remove_link(&dev->kobj, "driver");
+ klist_remove(&dev->knode_driver);
+
+ if (drv->remove)
+ drv->remove(dev);
+ dev->driver = NULL;
+ put_driver(drv);
+ }
+}
+void device_release_driver(struct device * dev)
+{
+ /*
+ * If anyone calls device_release_driver() recursively from
+ * within their ->remove callback for the same device, they
+ * will deadlock right here.
+ */
down(&dev->sem);
- if (drv->remove)
- drv->remove(dev);
- dev->driver = NULL;
+ __device_release_driver(dev);
up(&dev->sem);
}
-static int __remove_driver(struct device * dev, void * unused)
-{
- device_release_driver(dev);
- return 0;
-}
/**
* driver_detach - detach driver from all devices it controls.
*/
void driver_detach(struct device_driver * drv)
{
- driver_for_each_device(drv, NULL, NULL, __remove_driver);
+ struct device * dev;
+
+ for (;;) {
+ spin_lock_irq(&drv->klist_devices.k_lock);
+ if (list_empty(&drv->klist_devices.k_list)) {
+ spin_unlock_irq(&drv->klist_devices.k_lock);
+ break;
+ }
+ dev = list_entry(drv->klist_devices.k_list.prev,
+ struct device, knode_driver.n_node);
+ get_device(dev);
+ spin_unlock_irq(&drv->klist_devices.k_lock);
+
+ down(&dev->sem);
+ if (dev->driver == drv)
+ __device_release_driver(dev);
+ up(&dev->sem);
+ put_device(dev);
+ }
}
-EXPORT_SYMBOL_GPL(driver_probe_device);
EXPORT_SYMBOL_GPL(device_bind_driver);
EXPORT_SYMBOL_GPL(device_release_driver);
EXPORT_SYMBOL_GPL(device_attach);
projects / linux-2.6 / blobdiff